This study is a pre-post, open-label cohort study designed to investigate how a food-grade probiotic supplement affects biological measurements and wellbeing in healthy adults. Participants will take one capsule daily for either 1 month or 6 months.
During the study, participants will complete online cognitive tasks and provide blood and stool samples collected during home visits by trained staff. The samples will be analysed to explore changes in gut bacteria and other biological markers.
This study aims to understand whether the supplement is well tolerated and whether measurable biological changes occur. The study does not involve any experimental drugs or invasive procedures beyond blood sampling and stool collection, and participants will not be asked to change any current prescribed medications or treatments; with eligibility exclusions applying for recent antibiotics or immunosuppressants. The supplement is being studied for research purposes only and is not intended to diagnose, treat, or prevent disease. Participants will be invited to participate in a follow-up visit to assess long-term effects.
Aged 18 years or older at the time of providing informed consent.
In generally good health, with no known medical conditions that could interfere with the aims of the study or participant safety, as judged by self-report and screening questionnaire.
No history of significant psychiatric or neurological illness
Daily oral intake of a probiotic capsule
β-lactam antibiotics, macrolides, tetracyclines, fluoroquinolones, aminoglycosides, glycopeptides, sulfonamides, antimycobacterial agents, systemic antifungals or antivirals
Systemic corticosteroids, conventional immunosuppressants, biologic immunomodulators, targeted synthetic immunosuppressants, cytotoxic chemotherapy, or transplant-related immunosuppression.
A longer exclusion window is applied for systemic immunosuppressive therapies due to their prolonged and potentially lasting effects on immune function and gut microbial composition compared with systemic antibiotics.
Participants who commence systemic antibiotics or immunosuppressive therapy after enrolment will not be withdrawn from safety monitoring but will stop the supplement and will not continue the intervention phase of the study. With participant consent, data collected may still be used.